1. Field of the Invention
The present invention relates to an air-oil separating apparatus for an engine in which oil mist is separated from blow-by gases by a centrifugal oil mist separator into which blow-by gases are supplied from the engine.
2.Description of the Related Art
Known through JP-A-10-220215 is an air-oil separating apparatus for an engine in which a centrifugal oil mist separator for centrifugally separating oil mist contained in blow-by gases of the engine from the blow-by gases to return oil mist so separated to an oil pan is provided in a blow-by gas recirculation system for returning the blow-by gases from the engine to an intake system to thereby prevent the ejection of the blow-by gases into the atmosphere.
Incidentally, since conventionally, the centrifugal oil mist separator and a PCV valve for controlling the flow rate of blow-by gases are provided separately along a blow-by gas passage, there are caused problems that not only does a space required for installation of the centrifugal oil mist separator and the PCV valve need to be increased but also piping is required for connection of the centrifugal oil mist separator with the PCV valve and the number of man hours for assembling them together needs to be increased.
The invention was made in view of the situations, and an object thereof is to enhance the oil mist separating performance of an centrifugal oil mist separator by effectively incorporating a PCV valve into the centrifugal oil mist separator.
To solve the above object, according to the first aspect of the invention, there is provided an air-oil separating apparatus for an engine in which oil mist is separated from blow-by gas, comprising: a centrifugal oil mist separator into which the blow-by gas is supplied from the engine; and a PCV valve integrated into the centrifugal oil mist separator in such a manner that the PCV valve protrudes on an axis of a separation chamber of the centrifugal oil mist separator.
According to the second aspect of the invention, in the air-oil separating apparatus according to the first aspect, a protruding portion of the PCV valve which protrudes on the axis of the separation chamber of the centrifugal oil mist separator is formed by extending a valve seat of the PCV valve.
According to the third aspect of the invention, in the air-oil separating apparatus according to the first or second aspect of the invention, an oil separation plate is integrated into the protruding portion of the PCV valve which protrudes on the axis of the separation chamber of the centrifugal oil mist separator, and the oil separation plate is disposed between a blow-by gas inlet port for introducing blow-by gases into the oil separation chamber and a blow-by gas outlet port formed within the protruding portion of the PCV valve.
According to the fourth aspect of the invention, in the air-oil separating apparatus according to the first aspect of the invention, the oil separation plate is disposed between an upstream-side separation chamber to which the blow-by gas inlet port opens and a downstream-side separation chamber to which the blow-by gas outlet port opens, an external thread formed on an outer circumferential surface of a valve housing of the PCV valve is screwed into an internal thread formed in an inner circumferential surface of the upstream-side separation chamber so that the PCV valve is fastened into the centrifugal oil mist separator, the opening of the blow-by gas outlet port is provided to be situated inwardly of an inner end of the internal thread, and the oil separation plate is disposed between the inner end of the internal thread and the opening of the blow-by gas outlet port.
According to the fifth aspect of the invention, in the air-oil separating apparatus according to the first to fourth aspect of the invention, a separation chamber housing of the centrifugal oil mist separator and the valve housing of the PCV valve are integrally formed of a resin.